1. Technical Field
The present invention relates to a method for the production of multicolored printed images of computer stored information and more particularly to a method of using a single ribbon printer to produce colored printouts by use of a plurality of different colored ribbon cartridges and repeated printing runs.
2. Background Art
A computer having color graphic capability utilizes a color video monitor having the standard red, green and blue electron gun assemblies. The computers, at least those commonly available for home or personal use, use a color graphic system wherein each variant or shade of color, ranging across the spectrum from red to violet, and including black and white, are assigned an individual color identification statement. Hence, depending upon the capacity of the computer, the number of various shades of color are usually limited. For example, a small personal computers may have the capacity to graphically display 16 to 512 different shades of color.
The color identification statements are held in the compiler and are used to instruct the color monitor as to the particular combinations of red, blue and green electron beam strengths necessary to produce the desired color.
Printing a color graphic image from a computer is another matter. One method of reproducing a color graphic image from a computer onto a fixed medium such as paper is to employ individual colored inked ribbons for each color identification statement for which the computer is capable of reproducing. A second is to employ the three primary painting colors, red, yellow and blue in the various appropriate painting mixtures to reproduce the desired shade of color.
The first method identified above is not a practical solution in that printing devices are not available which can be utilized to automatically sort through and print from hundreds of differently colored inked ribbons. And usually multiple colored inked ribbons contain no more than five different, primary type, colors and as a result are only suitable for simple graphics and other displays which do not call for subtle shades or mixtures of color. Such a device is disclosed in TREZISE, ET AL., U.S. Pat. No. 4,469,459, wherein a color impact matrix printer has a plurality of individually color inked cartridges incorporated into the device which are selectively brought into engagement with the print head. The device is obviously mechanically complicated.
The second method of reproducing a colored graphic image is, as stated before, the mixing of primary inking colors of red, yellow and blue. By utilizing this method, a printer memory, whether it be stored in the printer, or in the compiler of the computer, must contain information to convert color identification statements from the color computer into instructions concerning the appropriate mixture of the three primary inking colors. This type of system will reproduce all of the color identification statements of the particular color computer in use, and generally allows for better color graphic capability, including the reproduction of more subtle tones and shades of colors.
Devices which take advantage of these features are similar to that disclosed in MATSUSHIMA, U.S. Pat. No. 4,586,055, which teaches a printer having an array of printing devices for imparting color to a fixed printing medium such as paper. It is also an expensive and complicated device. Similarly, LIU, ET AL., U.S. Pat. No. 4,594,597, also discloses a similar primary color mixture printing device which utilizes a rotating drum to make repeated passes with the fixed printing medium across a single printing device which prints from an array of internal different colored printing ribbons.
All three devices disclosed above are complicated, and not readily available for home or personal computer use. What is currently available for home or personal computer use is a wide variety of simple, inexpensive, single color dot matrix printers which have a single printing head and utilize removable inked ribbon cartridges.
What is needed is a method by which the currently and readily available, single color printers currently in use can be utilized to reproduce multicolor computer images either by the use of a preselected, limited number, of interchangeable color inked ribbons or by the blending of primary color inked ribbons to match computer color identification statements.